Question

检查图片的两侧。我试图让背景具有不透明度，而不会影响我放在它上面的内容。（我不希望文本也具有不透明度）但问题始终是我的图片的边没有不透明的事实。

.container {
  position: relative;
  background-image: url("https://www.elephantsdeli.com/wp-content/uploads/fly-images/1673/elephants-delicatessen-sack-lunch-order-form-hero-image.jpg-1920x1080.jpg");
  height: 50vh; 
  background-position: center;
  background-repeat: no-repeat;
  background-size: cover;
}

.background {
  height: 100vh;
  background: rgba(255,255,255,.4)
}

.text-center {
  padding: 50px 0;
}

<link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.1.0/css/bootstrap.min.css" integrity="sha384-9gVQ4dYFwwWSjIDZnLEWnxCjeSWFphJiwGPXr1jddIhOegiu1FwO5qRGvFXOdJZ4" crossorigin="anonymous">

<div class="container">
  <div class="background">
    <h1 style="font-size: 350%;" class="text-center"><b>It's Lunch-Time!</b></h1>
  </div>
</div>

Answer 1

Bootstrap 4有你的后背

只需添加这些类h-100，它们将为您提供高度：100％和px-0，这将为您提供零填充到X轴

<link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.1.0/css/bootstrap.min.css" integrity="sha384-9gVQ4dYFwwWSjIDZnLEWnxCjeSWFphJiwGPXr1jddIhOegiu1FwO5qRGvFXOdJZ4" crossorigin="anonymous">

<div class="container py-0 h-100">
  <div class="background">
    <h1 style="font-size: 350%;" class="text-center"><b>It's Lunch-Time!</b></h1>
  </div>
</div>

PS你也可以删除container，只要你不使用会导致溢出的row类（因为行有margin-left:-15px和margin-left:-15px）< / p>

Answer 2

您应该使用d-flex，align-items-center和justify-content-center代替自定义text-center样式。此外，不要将行的高度设置为fixed数字：让它占据容器的整个高度。

＆＃13;

.container {
  position: relative;
  background-image: url("https://www.elephantsdeli.com/wp-content/uploads/fly-images/1673/elephants-delicatessen-sack-lunch-order-form-hero-image.jpg-1920x1080.jpg");
  height: 50vh;
  background-position: center;
  background-repeat: no-repeat;
  background-size: cover;
}

.background {
  background: rgba(255, 255, 255, .4)
}

＆＃13;

<link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.1.0/css/bootstrap.min.css" integrity="sha384-9gVQ4dYFwwWSjIDZnLEWnxCjeSWFphJiwGPXr1jddIhOegiu1FwO5qRGvFXOdJZ4" crossorigin="anonymous">

<div class="container">
  <div class="row background h-100">
    <div class="col d-flex align-items-center justify-content-center">
      <h1 style="font-size: 350%;"><b>It's Lunch-Time!</b></h1>
    </div>
  </div>
</div>

＆＃13;

Answer 3

如果要使用bootstrap 4功能，则必须关注其规则。其规则规定container必须包含row，row必须包含col。在这种情况下，您的标记将显示为您想要的。

＆＃13;

.container {
  background-image: url("https://www.elephantsdeli.com/wp-content/uploads/fly-images/1673/elephants-delicatessen-sack-lunch-order-form-hero-image.jpg-1920x1080.jpg");
  height: 50vh; 
  background-position: center;
  background-repeat: no-repeat;
  background-size: cover;
}

.background {
  height: 100vh;
  background: rgba(255,255,255,.4)
}

.text-center {
  padding: 50px 0;
}

＆＃13;

<link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.1.0/css/bootstrap.min.css" integrity="sha384-9gVQ4dYFwwWSjIDZnLEWnxCjeSWFphJiwGPXr1jddIhOegiu1FwO5qRGvFXOdJZ4" crossorigin="anonymous">

<div class="container">
<div class="row">
  <div class="background col">
    <h1 style="font-size: 350%;" class="text-center"><b>It's Lunch-Time!</b></h1>
  </div>
  </div>
</div>

＆＃13;

如何修复bootstrap不透明度？

3 个答案: